If the trolley has an e unit then I believe Z Stuff offers an automatic reversing unit. I use a Pocono Mountain Lines auto reverse board in a similar manner. Distance is not an issue with either, the reverse sequence is based on activating the relay on the board. I think the Z stuff board requires isolated rails, the Pocono mountain lines requires isolated center rails, three sections, the two ends where the trolley would reverse and a running section which can be whatever length you desire. I have an extra one if you decide to go this route.